With the advent of sophisticated computers, facsimile machines, printers, and other computer-related electronics equipment, the need for an external printed circuit (PC) interface to be used by the computer and computer-related equipment is ever increasing. To this end, PC cards containing external memory and data to be used in computer processes have been designed. At the present time, there are three different PC card types, as defined by the Personal Computer Memory Card International Association (PCMCIA). This is the standards body responsible for developing the 68-pin PC card standard. The three PC card types, are as follows:
a. Type I PC Cards are the same width and length as a common credit card, 54 mm.times.85.6 mm, but are thicker than a credit card. The thickness of a Type I card is 3.3 mm (0.130").
b. Type II PC Cards are used by those companies which are utilizing memory components that are too high to be housed within a Type I card. Type II memory cards are also the same overall length and width as credit cards, but have raised body cross section in the substrate area which gives them an overall thickness of 5 mm (0.195"). The raised substrate areas of these cards are 48 mm in width.
c. Type III PC Cards are the result of a recent movement sponsored by the Small Form Factor Committee (SFF) to enable 1.8" Small Form Factor Disk Drives to be plugged into memory card connectors in small portable computer applications. Type III PC cards are the same length and width as Type I and Type II PC cards. However, Type III cards have a substrate area thickness of 10.5 mm. Also, Type III PC cards require a card guide opening width of 51 mm of the header connector to accommodate the slightly raised substrate area.
There is a move afoot to develop specialized or multi-purpose memory cards, such as described in the concurrently filed co-pending application. This move has increased the need to provide greater stability to the frame kit containing the memory card.
By way of brief background, memory card holder or frame kit assemblies, comprise a printed circuit board, a casing or frame made of an insulting material for receiving the printed circuit board, metal shielding covers, and at least one connector, typically referred to an "I/O" connector. The connector is provided on one end of the casing or frame for interfacing the memory card, and particularly the printed circuit board contained in the casing, to the computer equipment to which the card is mated. The connector is designed to extract the contents of the memory stored on the printed circuit board and to bus data to and from an outside environment, which also usually comprises a computer or other electronic equipment. In this fashion, data traverses the interface between the PC card and the outside environment so that the data can be efficiently transferred and used by the computer to which the card is mated for its intended purpose.
PC cards are generally interchangeable and can be used with many different machines and electronic components. Because the PC cards are interchangeable, they undergo a significant amount of abuse when transported, interfaced and mated to the different computers and electronic equipment which use them. Since a PC card is conventionally made up of a number of layers and/or elements glued or otherwise bonded together, the individual layers tend to become loose and/or separated from one another as the memory card is subjected to flexing or torsional stresses, as may occur when the card is inserted into or removed from the electronic or other computer-type equipment. Thus, even after moderate amounts of usage, conventional memory cards have heretofore frequently become structurally loose, and the internal members of the card often become misaligned. This results in failure of the PC card and degrades the performance of the electronic equipment which uses the card. These undesirable results generally induce poor performance of the computer system which uses the memory card.
In U.S. Pat. No. 5,339,222, there is disclosed a memory card holder that provides a good degree of structural integrity to the assembly by the use of a pair of interfitting metal sheet-like cover members. Additionally the invention thereof provides continuous shielding against distortion of data signals between the PC or memory card and the I/O connector.
As an improvement to such prior art, U.S. patent application, Ser. No. 08/292,913, now abandoned, was recently filed in the USPTO, which application is assigned to the assignee hereof. The contents of the co-pending application is incorporated herein in its entirety. Briefly, the improved feature of the invention thereof is the provision of a first cover member of the frame kit having an inner planar surface in close proximity to the memory card, where the surface includes a torsion resistant, strengthening member bonded thereto. Preferable the strengthening member comprises a thin film of a thermo bonding plastic, where such bonding is achieved by the application of heat and pressure.
In a recent patent, U.S. Pat. No. 5,397,857, there is disclosed a memory card package which includes a pair of stamped and formed metal covers, each secured to a plastic frame element. The plastic frame element is injection molded around a plurality of fingers which extend from the periphery of the respective cover member. Further, the plastic frame element extends beyond the plane of the metal cover to expose a perimeter. By this arrangement, apparent bonding of the two covers is facilitated, where a preferred manner of bonding is by sonic welding.
The present invention offers an alternative approach to torsional resistance by providing peripherally arranged pins and sockets, press fit to one another, as the preferred means to secure the respective cover members to each other. This and other features will become apparent in the description which follows, particularly when read in conjunction with the accompanying drawings.